﻿using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
using System.Web;

namespace System.Web.Mvc.Html
{
    public static class CustomHtmlExtension
    {
        private static Type GetNonNullableModelType(ModelMetadata modelMetadata)
        {
            Type realModelType = modelMetadata.ModelType;

            Type underlyingType = Nullable.GetUnderlyingType(realModelType);
            if (underlyingType != null)
            {
                realModelType = underlyingType;
            }
            return realModelType;
        }

        private static readonly SelectListItem[] SingleEmptyItem = new[] { new SelectListItem { Text = "", Value = "" } };

        public static string GetEnumDescription<TEnum>(TEnum value)
        {
            FieldInfo fi = value.GetType().GetField(value.ToString());

            DescriptionAttribute[] attributes = (DescriptionAttribute[])fi.GetCustomAttributes(typeof(DescriptionAttribute), false);

            if ((attributes != null) && (attributes.Length > 0))
                return attributes[0].Description;
            else
                return value.ToString();
        }

        public static MvcHtmlString EnumDropDownListFor<TModel, TEnum>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TEnum>> expression)
        {
            return EnumDropDownListFor(htmlHelper, expression, -1, null);
        }

        public static MvcHtmlString EnumDropDownListFor<TModel, TEnum>(this HtmlHelper<TModel> htmlHelper,
            Expression<Func<TModel, TEnum>> expression, int selectedItem, object htmlAttributes)
        {
            ModelMetadata metadata = ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData);
            Type enumType = GetNonNullableModelType(metadata);
            IEnumerable<TEnum> values = Enum.GetValues(enumType).Cast<TEnum>();

            IEnumerable<SelectListItem> items = from value in values
                                                select new SelectListItem
                                                {
                                                    Text = GetEnumDescription(value),
                                                    Value = value.ToString(),
                                                    Selected = value.Equals(metadata.Model)
                                                };

            // If the enum is nullable, add an 'empty' item to the collection
            if (metadata.IsNullableValueType)
                items = SingleEmptyItem.Concat(items);

            return htmlHelper.DropDownListFor(expression, items, htmlAttributes);
        }

        //http://stackoverflow.com/questions/434604/how-to-i-find-the-absolute-url-of-an-action-in-asp-net-mvc
        public static string AbsoluteAction(this UrlHelper url, string action, string controller)
        {
            Uri requestUrl = url.RequestContext.HttpContext.Request.Url;

            string absoluteAction = string.Format("{0}://{1}{2}",
                                                  requestUrl.Scheme,
                                                  requestUrl.Authority,
                                                  url.Action(action, controller));

            return absoluteAction;
        }

        //http://stackoverflow.com/questions/15716815/how-to-create-menu-by-actionlinks-in-mvc4-razor-view
        public static MvcHtmlString MenuItem(this HtmlHelper htmlHelper, string text, string action, string controller)
        {
            var li = new TagBuilder("li");
            var routeData = htmlHelper.ViewContext.RouteData;
            var currentAction = routeData.GetRequiredString("action");
            var currentController = routeData.GetRequiredString("controller");
            if (string.Equals(currentAction, action, StringComparison.OrdinalIgnoreCase) &&
                string.Equals(currentController, controller, StringComparison.OrdinalIgnoreCase))
            {
                li.AddCssClass("active");
            }
            li.InnerHtml = htmlHelper.ActionLink(text, action, controller).ToHtmlString();
            return MvcHtmlString.Create(li.ToString());
        }
    }
}